ABSTRACT:
The study of polyelectrolyte complex (PEC) of oppositely charged polymer has great potential in the field of controlled and targeted delivery. The objective of present work was to study oppositely charged polymers by evaluating their effect on various factors of hydrogel. In proposed study, chitosan (CTN), a natural polymer of cationic nature and ?-carrageenan (CGN) and xanthan gum (XGM) polymers of anionic nature were selected and used in different polymer ratio. Complexes between oppositely charged polymers i.e. CTN-CGN and CTN-XGM were used in design to control the release of drug diclofenac potassium (DFP). The oppositely charged polymer forms PEC which controlled the release of drug from polymer matrix, as single polymer do not shows this effect. The polyelectrolyte complex (PEC) thus formed were loaded with DFP which is anionic in nature. In vitro releases of drug, viscosity of plain polymer alone and in combination were measured. When CGN existed in an aggregated helical conformation, the interaction with CTN produced PECs with a charge ratio of CTN to CGN below unity. The interactions between polymers were studied using differential scanning calorimetry (DSC) and Fourier Transform Infrared spectroscopy (FTIR) study. The reasons for controlled release of DFP from CTN matrices at different pH include poor aqueous solubility of drug, formation of a rate-limiting polymer gel barrier along periphery of matrices, interaction of DFP with protonated amino group of CTN, and the interaction of ionized amino group of CTN with ionized sulphate group of CGN and carboxylic group of XGMZ.